Final update! The map was changed to std - this didn't make the noise disappear. The Garrat turbo gave up the ghost last Saturday (didn't last very long). It was towed back to the garage, they had to empty the exhaust & intercooler of oil (it was a right mess). Since having another garrat turbo ...

an update. The 3 remaining pipes were changed, they haven't cured the noise. As it only happens when you're giving it the full beans, we're going to live with it for now (the wife drives it the most). Hopefully one day it'll be sorted, but until then.....  O:-)

Thanks for all the replies guys. The garrett turbo was fitted as the 1st one had oil starvation due to the high pressure feed pipe being blocked. It was installed by an indy that services 3 other cars that belong to the family Z4m, E220 & 640d. We've never had an issue with him, but this seems to ...

Thanks Ian. Are some more prone than others to split? Which hoses do I need? Are they changeable by a DIY mechanic (me) or is this best left to an Indy to sort???

Hi all, The turbo blew up after 100k miles, so it's been replaced with a Garrett one. Since then, around 2.5-3k revs under load there is a squealing noise (similar to balloon having the air released when pinched). The turbo has been doubly checked, it's fine, so is this one of the many pipes that ...